nginx with custom modules crashes in gzip crc32()

[artemg]

agentzh, thanks for the answer, seems the problem is really with zero
size bufs. I changed code to insert spaces, if buffer is empty and
everything start to work with gzip disabled (before that nothing worked
with gzip off), and I think there will be no crashes in gzip now if
enabled. Now I will create my own chains to pass to downstream filters.

I didn't try valgrind because usually it consumes a lot more cpu, and
this is unacceptable on staging machine(there will be high cpu load, or
I will need to decrease number of requests so I will wait for crash more
time). But thanks for reminding about it.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,216804,216893#msg-216893